Monday, June 11, 2012

Storm Damage from June 10, 2012

Considerable damage was sustained from a severe storm in Highland Park, St. Paul. There were no sirens prior to the storm. Here are a few glimpses of damage that occurred within a few short blocks of each other. We counted at least five trees that landed on cars and several streets and alleys were impassable. Trees generally seemed to fall in a southwest-to-northeast direction.

With wind gusts reaching 59 mph at MSP, approximately three miles away, it seems like that winds approached or exceed 70 mph in this area.

Based on radar imagery (reflectivity, radial and storm-relative velocity) this event definitely yields to a straight line wind event with a possible microburst .. curious if tree damage in a fan pattern or not. Definitely was seeing development S of metro as it roared NNE into the Twin Cities. Low and upper level winds were definitely supportive of a straight-line wind event. Siren policy varies and confusing and a whole different topic. But, can't say sirens were warranted in this event.

Definitely a microburst - no indication of a tornado. I'm at Snelling and Randolph, and we had some major tree limbs go as well. I was standing outside during the downdraft - can *estimate* winds definitely over 50mph coming from the SSW.

I like the set up coming in for Thursday. Warm front will be nearby that will help to add some spin. Airmass is going to be quite unstable in the warm sector. What makes this one different compared to the previous couple events is that this one will have more shear to work with. At this point, I think areas around the metro and to the west and north will have the highest tornadic potential Thursday evening...but a good chunk of southern and central MN, and western WI will have a chance at seeing some tornadoes Thursday evening and night. Keep a close eye on this one, and remember that warm fronts area already sheared and carry instability so we don't have to see sunshine to make things fire on a warm front.

@Duane,question for you,you say you 'like' the set up for tommorrow.What exactly do you mean by that?,are wanting/liking severe weather to occur?I for one wouldn't like to root for severe weather to occur,because as the above pictures depict,it disrupts and effects lives.Is it cause your a storm chaser?Anyhow in a round about way,thanks for the heads up! -Karl

Hi Karl. Yes, as a matter of fact I am a chaser and just overall weather enthusiest. I don't hope for death or destruction, and while I do usually hope to see a tornado or two I would rather see them over a wide open field and away from any town, village, city, or home in general. I also know that there is really nothing that can be done when it comes to what mother nature will do. I like severe storms in the summer as much as I like snowstorms in the winter. A lot of weather enthusists will imply that they like a set up when it comes to severe or winter storms, but it certainly doesn't mean that we want the destruction that comes with it. I hope that all makes sense. Anywho, keep an eye to the sky tomorrow evening, as things could get bumpy.

Well, I realize that there was some flooding and wind damage in some areas, but all things considered I think a lot of eastern MN and western WI lucked out today. Morning storms really kept the sun from coming out, and kept temps down through the day. Had we had a lot of surface heating and instability build today, I believe it would have been close to a tornadic outbreak. Shear values were quite high at all levels and had it been able to really tap into more energy there would have been no problems getting storms to spin. I think the storms and boundaries from earlier slowed the warm front way down so storms were able to just keep reforming and train over the same area. Today was just the start of an active period. Saturday is the next day to watch for most of MN especially if we get sun that day. Monday would be the next one to watch after Saturday...with Wednesday of next week being watched as well by the NWS. Buckle up because it is going to be a bumpy ride. With a lot of rain that fell today, it wouldn't shock me to start seeing some flood watches down the road if more heavy rain is expected.

Can you tell us what maps/data you're looking at to get shear values? And what range of shear values is a concern? I'm really interested in learning how severe weather develops.

It would be really cool to see a page that shows examples of various mechanisms that go into storm formation. Maybe I could put something together. Maybe we pick a big recent storm and lay out maps and data that preceded the storm, giving a clear picture of what factors when into the formation over a couple days or even weeks. Thoughts?

Hi Disco80. The page I look at is the SPC's mesoscale analysis page. It updates often, and is really a one stop shop. The site is here http://www.spc.noaa.gov/exper/mesoanalysis/new/viewsector.php?sector=13

It's nice looking at the shear maps, because they only display values that are high enough to cause concern. I have often thought about doing that as well, but just haven't had the time to really go back and see what happened. Maybe someday though!

Wow, the SPC was right to highlight a lot of MN and WI in a severe risk in their day 4-8 outlook. I see no reason why there shouldn't be a higher end slight risk when the Day 3 comes out. Models are showing an incredible amount of instability building (CAPE values exceeding 4000, when anything in excess of 2500 is considered very unstable), with 0-1km and 0-6km shear values more than sufficient to support supercells (0-1km is 25 knots, and 0-6 is close to 50 knots). If this trend continues, a moderate risk may end up being needed once it gets closer to Monday. This is certainly something to watch over the weekend...but if if any trigger slows up, things could be delayed to Tues. The southwest flow continues right through the first half of next week, so things should remain active until that ridge to our east moves further east. Another thing to note about Monday is that there are signs that the line of storms that does form could end up training, and more flooding could occur if that happens. All things to watch as we get closer to Monday.

I look at all three CAPE options...surface based, mixed layer, and most unstable. However, this bufkit program I use doesn't specify which one it is. It just has a general CAPE number. I find it interesting that the SPC has us in a slight for Monday, yet the NWS is focused on Tues/Wed. Personally it wouldn't surprise me to see three straight days of at least slight risks due to the boundary stalling out. If temps get too warm aloft, then things will end up being capped off and storms won't fire. Regardless, I really think Mon through Wed all have potentials for severe weather. Flooding concerns are there as well, again due to the front stalling out.

Higher end moderate risk issued for SW Minnesota in the new Day 1 (which covers Sunday). Hatched tornado and hail risks, with a good wind threat across southern MN as the storms go linear. If you live in those areas, stay aware. If things evolve as forecast, there could be a pretty decent bow echo that moves across southern MN...but this could of course turn even more towards IA and only graze the far southern MN counties. Day 2 still is only at 15%, but those risks could easily go up eventually. Day 1 went from being a lower end slight risk, to a higher end moderate risk in the matter of one update. Stay tuned!

Hi my friend! I wish to say that this post is awesome, nice written and include almost all important infos. I would like to see extra posts like this. Check telephone answering service for best Telephone Service.